Hirobo 44Bs and Zerda :-)

[silvertriple 4084]

I did search my Hirobo stuff to understand how many cars I could rebuild. The Hilux 44B came complete except the bumper, so the transmission was complete. So there will be at least one. Looking at my stuff, I'm already sure I'm missing two complete diffs, out drives and dog bones for a lonw wheel base chassis. For the rest, it should be fine at the exception of the screws and other hardware...

While searching the elements, I found the number plate of the Zerda, so it was the perfect moment to put them on (before I forget to do this)...

There is not much room to put stickers on this car, and there is too much conflicting sponsors on the stickers sheet anyway, so I used only few... At the end, the number plate are making the ensemble more balanced, but there is still something disturbing me when I look at this car. May be the rear wheel need to be larger...

[silvertriple 4084]

Some of my topics have no end :-)
I have this body in my radar for quite a long time, and a friend have one, and proposed it to me with a 44B chassis and a Rock'n City box (in which he put the chassis and the Lancia bodyshell). We discussed this few months ago, as he wanted to separate from some of his cars to make room for others... It obviously had a cost, but I really like this bodyshell. And it comes with an original set of stickers...

And the box is a nice addition, although its state show its age...

That said the bodyshell is missing to elements : the search lights ramp at the front, and the wing at the rear. I'll try to do something about this. And I already contacted my friend who reproduced the 44B Hilux bodyshell, and it seems he is interested to reproduce it (By the way, he confirmed me he's doing this in a non destructive manner and should be able to do it for this Lancia, and by the way he needs to send me my Hilux body back)...
(and If ever you have the two missing items unused in your stash, you may contact me)

[stulec52 54]

as a fellow Hirobo fan  (Current Rock N City and Hilux owner, also past Zerda owner and racer) I just wanted to say how much I've loved this thread.
 So much awesome work and huge amounts of time have gone into it 
 very well done !!

[silvertriple 4084]

On 5/4/2024 at 4:29 AM, stulec52 said:

as a fellow Hirobo fan  (Current Rock N City and Hilux owner, also past Zerda owner and racer) I just wanted to say how much I've loved this thread.
 So much awesome work and huge amounts of time have gone into it 
 very well done !!

If you loved this thread, you may be interested in my Marui threads, as well as my Nichimo threads, and this even if you are not a Marui or Nichimo fan...

[stulec52 54]

On 5/5/2024 at 4:33 AM, silvertriple said:

If you loved this thread, you may be interested in my Marui threads, as well as my Nichimo threads, and this even if you are not a Marui or Nichimo fan...

I'm an old school racer.
 So, for me it's about the stuff I raced BITD, which included Kyosho, Schumacher, Mardave, Yokomo, Losi, Tamiya and Hirobo.
Not much else floats my boat I'm afraid

[silvertriple 4084]

Marui was clearly underared, but it's impaction the hobby shouldn't be put aside: I can tell you that all their 4WD were actually raceable... Something that can't be said about Nichimos... 

[silvertriple 4084]

Tomorrow is the first vintage of the season, and I'm late on my plans... Thanks, I'm off today, so that give me some possibility to do something about this...
I could go with the already built 44B Hilux, but it is too nice for this. The plan was always to have a runner based on printed parts for suspension. I have everything to build one, it is just a question a building it. I have a bit of work for this:
- Paint a second bodyshell, in a light color scheme. Which is still to be defined at this stage (will the inspiration come within the day?).
- Build the chassis with the already printed parts. Normally, I have everything for this, except the radiobox lid, for which I just launched a print...

I may also want to print some of the accessories for the bodyshell, but in resin this time...

[silvertriple 4084]

Ok, I must confess something now... I've been totally over optimisitic this time... There was some progress, but it won't be enough to get a 44B Hilux for the week-end, and I don't want to use the other one...

First, I tend more and more to rely on auto oreintation on Bambu Studio, and it seems it works better and better. I printed the radio box lid, and the result is much better than last time I print the same file in a different orientation I set myself... Th eprint is in ABS and it will work perfectly.

I also printed a front belt cover, relying this time again on auto orientation...

The prints were this morning... Although I woke up early, I did some exams in the early morning, and I only really started to work around 11... And I got caught offguard when my wife call me to tell me it was time for lunch (she was working remote today). Not much was done in the morning, except launching few prints, and manage a print failure on resin side...

Early this afternoon, I took care of the second 44B bodyshell I have. I decided I'll go for white... The bodyshell did not have overspray film as it was the first ever made from the mould and my friend remove the overspray film to see what was happening while vacforming the body, to potentially add few air channels here and there... Therefore, I had to find a way... Last time I did with masking tape, and it is far from practical as you don't see what is happening. I did differently this time...

And here is the result of the paint...

I'll have to add the stickers and the accessories (printed in resin, for some of them)...

Then I started the build... The gearboxes are well in place, and the original radiobox fits perfectly in the space (I had absolutely no doubts, but still. Here, it is printed gearboxes).

Unfortunately, I'll have to reopen the gearbox : i bought the ball bearings for the 44Bs and Zerda before this one arrive. I had still ball bearing for the axles, but not for the rollers... I lost a lot of time searching for them, and finally check, and the fact that some of the rollers had bearings and some not did not really help... In short, this car won't be ready for Montluçon, but it should be for Belley or Perrex (two events in june)...
 

[silvertriple 4084]

While back from Montluçon, I reshuffle some boxes in the work area... And found some ball bearings allowing me to resume work on the 44B Hilux... I reopen the gearbox and replaced the rollers bushings by ball bearings...

Then I started to work out the suspensions... You may note the double bearing adapter. I used all the one I had until now for the Zerda, Hilux and Rock'n City, so I had to reorder some. When I searched, I found some ABEC-5 ball bearings which were not much expensive than the usual version I found... We'll see if it changes something (which is very much possible). The pivot balls are bigger than the original ones and the links will have to be shorten, but I'm not much concerned: I want to test PETG to the limit, so I prefer to break the parts rather than having a pivot ball free...

There was quite an effort to prepare the suspension arms : holes needs to be drilled to the right diameter.

And arms are in place...

And soon I added the dogbones and the upper arms...

I modded the pivot ball support at the rear right to give slightly more space for the link. it was absolutely required. I'll add steering next and as well shocks (Kyosho re-release for this one). But that will be for next step...

[silvertriple 4084]

I did not have time to finish the car before Montluçon last week, but the target is to have the car running next week-end, in Belley...

First, I did some work yesterday on the bodyshell... Resin printed parts look like original ones...

I put the key stickers there... It is difficult to get them right. I'm sure I'll be able to get it even nicer next time I do a 44B bodyshell...

I've fixed all accessories. Mirrors are set to be temporary and removed when running.  And I also add one sponsor sticker on the car. It's not properly vintage, but it is all about vintage, so I profit to make a bit of advertisement for the excellent rc-paper.com website :-) (I do not have any compensation of any sort, and I even paid for the stickers)...

I then put the bodyshell on the other chassis to see what it will look like. I'm not sure if I add anything or not... Time will tell.

Back on the chassis. I replaced a few parts as I did a mistake : front gearbox parts were printed to work with 3mm shafts for suspension arms. I reprinted them with the standard 2.5mm shafts. I also rework the c-hubs, as I discover that I made a mistake when modelling them, and it was corrected quickly. The front end as no slop anymore, just like the rear.

As mentioned earlier in the thread, this car will run Kyosho red shocks (optima re-release). Setup I used was quite simple as all needed parts are on the shocks clusters :
- front - 2mm removed to the range by using a a 2mm ring outside the shock chamber
- rear - 6 mm removed to the length by using a 6mm thick ring inside the shock chamber

I just printed some collars with included pivot balls (I did not have metal one anymore so that was probably simpler :-). I could have gone red, but I decided to go black.

Shocks are now in place. The rear shock tower is positionned like it is on a Zerda to give more rooms around the shocks for the arms.

Here is the current progress

Remains to do before we can call it done :
- put the steering in place, as well as the rx and esc
- add a driver figure (thinking about a Samurai driver as it seems to be the right scale - but I may cut a Super Wheelie driver as well)
- print a bumper and install bumper and winch

[silvertriple 4084]

Electronics is done...

A few settings were required for the direction as the angle is very limited...
I'll probably won't have the time to print tires for this car, but I may used some Scorpion rear with the original rims (I have a set of rims and a friend just tried that as I was mentioning they may work well together with Scorpion re-release tires). I have some on order, and they should arrived within the week.

Beside this I still have to print a Bumper (I have one printed in ABS, but i'm not sure it will work nicely. I may want to try TPU instead. TPU is a nightmare for supports, but printed splitted and glued that should not be an issue. The real question is how to make the bumper rigid enough so it does some work... Anyway, I'll find a solution and this car will run (until a break a PETG printed part) next week :-)

[silvertriple 4084]

I've designed a support for the driver figure. It works with a Samurai driver, but could ultimately work with anything with a bit of modifications...

It's currently printing, and it will require 2 minutes effort to put it in place at the end...

ABS bumper is in place, and I'm thinking than maybe a mixed part with TPU and ABS halves could do the job...
 

[silvertriple 4084]

While I have some Scorpion re-re rear tires on order (they are shipped, but should arrive on Thursday or Friday), I did found a set of two in my stuff...

I put it on the set of rims I have without tires...

The internal ring keeps the tire in place firmly, and since the profile is not exact, it doesn't fit symmetrically on the rim. That said, the front side is a bit rounded, and that will protect the chrome side, while the rear is flat... That should definitely work. I check the dimensions next to original tires, they are slightly larger, but diameter wise this is perfect.
And I also found that there was another easy possible solution which should work easily for any 44B car (it would be the same for Zerda by the way)...

Only waiting for the tires on order to arrive. The ones I have here may be soft while the other ones are medium, but that should not be an issue : I'll probably put the set of soft at the front while the medium will be at the rear...

[silvertriple 4084]

Tires arrived today and they were promptly mounted on the car as the driver was quite impatient... I probably need to add some preload on the front but beside this not much to adjust...

I also took pictures with the one built like the original, this should make easy comparison between the original tires and the Kyosho Scorpion 2014 rear tires...

[silvertriple 4084]

Beside the Bearcat SS you can see the video in the ad'hoc thred, I ran as well the 44B Hilux with its printed parts, kyosho shocks and tires...

And it is great on the track. Although short, which requires to pay a bit of attention when turning, it's great car and easy to handle. I was really surprised how balanced it is during jumps as it stays flat, which means the balance is near perfect...
My son took again a video (which is the assembly of two actually). The noise you can hear is not due to belt skips, but is due to the bodyshell rubbing on the printed bodymounts... I solved this later with some o-joints...

 

[silvertriple 4084]

I got contacted by someone searching for a Zerda bumper... I never tested it, so printed one in TPU to see...

The dimensions, profile and holes position are perfect, only the cuts profile are not perfect. I may do something about it at some point, but for the time being if any one needs a bumper for a Zerda, you may contact me.

[silvertriple 4084]

While I had a 44B Hilux with quite a few printed parts (FDM) running during the vintage event this season, there is a few things left on my todo list for this project for parts publication :
- put parts in clusters for SLS/MJF nylon prints
- review the radio box for 44B-LWB chassis : while doing some supports, I noticed one measure was wrong, and unfortuntaly, the radiobox and the lid will need a major rework
- zerda parts testing (mainly the belt cover, which I have a reasonable doubt due to the mistake seen on the 44B LWB chassis, so I want to check it)

Beside this, I also have in mind one single picture with a few 44B chassis. I was lucky and found other 44B LWB chassis which should allow me to rebuild a 44B Rock'n Vega, a Lancia 44B, and a 44B Racing Baja  : I will have to work out a mold for this bodyshell. The Lancia 44B will rely on Nylon PA12 SLS 3D printed parts, dyed red (I need one of those chassis to show case the prints, although I'm 100% sure they are right for dimensions as I have the FDM version already running).

In the meantime, I worked out the clusters for both 44B and Zerda suspension parts.

I will need to check if there is enough room in the belt cover to pass a GT2 belt, as if it is the case, I may be very well go for a GT2 puley set printed in nylon...

[silvertriple 4084]

My 44B-LWB chassis plate was 1mm to short... 336 instead of 337. I noticed that when making supports for my 44Bs. The radio box was therefore having a mm issue somewhere...
The fact is : most of my parts relied on that single chassis plate. Move the rear of the chassis plate and all goes with it: dependancies are a nightmare in that case in (con)fusion360.
Reworking the radiobox required a review of the rear gearbox side (which I know at 100% sure to be right in initial design). I decided to break the link with the original design of the chassis plate to remove the dependancy to make it easier to work out the radio box. if not, I have to redo the gearbox sides, with all risks of making it incorrect.
After a morning debugging, my radio box should be good now. I'll print one in PLA to check it is fine.
Next is the radio box lid...

[silvertriple 4084]

Finally my radio box is good. I printed one in PLA for testing. The lid is currently printing. Next will be one picture with mix printed radiobox and lids...

Even the supported side don't look too bad, this should be quite easy to post process for a nice finish...

I assembled the parts further...

There is a few parts I can't validate right now : many of the Zerda parts are too long for this. Worst case scenario, I will have to get a Zerda printed for the cause (which means I need to find a way for the transmission, as I have no diff for one additional car in the plan).

[silvertriple 4084]

The lid was printed. It goes nicely on both radio box (the original one and the printed one, just like the original one). That being said, I made an additional test, this time on the 44B City. This is the only car where the roll bar is fixed at the rear of the radiobox; other bodyshell relies on the rear body mounts. It was good that I made this test, as I could notice that the lid was difficult to put in place. I modified the design accordingly, and it will now be fine...

For the Zerda, the main belt cover is possibe to print on my X1C. I decided to print it, and to print the chassis splitted : I will use the belt cover to attach the two half parts to check the dimensions properly, after having check the belt cover is having right dimensions...

I also modified the pulley belt cover to give a bit more space around the 55T pulley. This will go for a test print as well over the week-end...

Speaking about pulleys, long time ago, I thought one element that could be consider to make those cars more suitable to nowadays way of running a car would be to convert the pulley to Powergrip GT2 standard. This would allow to run with more torque, and likely less belt skip. This is not really an issue on the 44B, as the chassis is rigid enough on those, but on the Zerda, this is slightly different : if you want to avoid belt skip, you need to get the belt tight, and that means loosing autonomy, and the chassis flex, which is an advantage in some conditions. A powergrip GT2 train would definitely make the things better. That being said, a GT2 belt is thicker than the MXL belt. The kickup of the Zerda might be an issue for this as the belt sides are not running parallel. But apparently, this would work.

I believe I have already the 55T pulley and the diff body somewhere in GT2, because that's the way I initially model them for the Bearcat SS. I will check this, and if not I'll redo them.

[silvertriple 4084]

Looking back in a massive project like this is sometimes hard... Specially when you have lot of dependancies...
The Belt cover for the Zerda is printed. It will require a review to reinforce it : it broke on the front area when removing the supports.
Now, while the center are is good, the front area needs to be reviewed as well: there is an issue in the are where it joins the front gearboxes... Probably linked to the fact that some projections are lost due to some manipulations in one of the files it depends on, and even though I have a valid projection after relinking it, I can't find a way to get the line matching what it should : this screams redo the front part. (I love when a plan comes together :-) )

[silvertriple 4084]

Few test prints done...

The chassis splitted is printed as well

I did some checks and it looks good.

 I had not much doubts on the holes positions, as they were already corresponding to the belt cover...


Each hole allow to see the screw head under it...

The profile and size are also good (the front cut on the side is not exact, but I do not see this as critical)

While the print was ongoing, I revised the belt cover file to introduce reinforcement (there was more work due to the fact some projections were lost). I'll do the same on the 44B front belt cover.

 

[silvertriple 4084]

Reviewed belt cover is printed (the non reinforced part broke at the front, which means I had to reprint it anyway).
I mounted one of the PETG printed gearbox walls, and fixed the two parts of the chassis together with the belt cover...

The rear profile matches with the rear original gearbox (not really a surprise, as my printed gearbox is matching the profile of the original radio boxe)... There is less and less doubts about the chassis and belt cover... I will still do one profile print aiming to check the position of the key screws at the front (I have no doubts at the rear anymore).

The printer is working currently : I'm printing a diff case to recheck it before doing a GT2 version...

[silvertriple 4084]

I printed the diff case, the pulley, and the pulley cover.

Everything is good (I think I already checked the diff case, but I can't see evidence in my recorded pictures). 
The next step is to work out a GT2 pulleys... The profile is a bit more complex, but it allows much bigger area of contact between the pulley and the timing belt, allowing for more torque and higher speed than MXL. And both timing pulley and timing belt are widely available (any 3D printer use generally GT2 belts).
 

[silvertriple 4084]

I made a pulley and a diff case suitable for GT2 standard. I will have to evaluate the belt length required for the Zerda/44B LWB and the 44BHilux.

On this image, there is both GT2 and MXL pulley. Powergrip GT2 allows more contact between the pulley and the belt, which means less wear, more torque, more speed, and less skips for the same tension...

I also printed some bevel gears to put in the diff to check them...

The fact is that I would miss some diffs internals if I want a printed Zerda, as well as diff cups, dog bones and axles... What if I get those printed in Metal?

At least, they are fine as printed parts are working properly in the diff body...

I have a lot of things done and ready.

I thought also about the axles. I could use other axles, and rework the knucles and the rear hubs to work with them and avoid the big bearing or the adapter to use double smaller bearings I made for the original parts... That is going to be one of my next activity.